Recently, my Biscotti has taken to, not only jumping, but biting and attacking when I go to feed him. It was cute at first, but his outbursts are getting really violent, and I am concerned for his well being, not just with jumping out of the tank, but with injuring himself when I react. Frankly, it is startling when he bites me, and if I don't see him and I a mucking around the tank for whatever reason (usually cleaning) he startles me into jumping. One time I almost squished him.

I guess it didn't help this time when he jumped and bit me I was giving him his first EVER meal of blood worms...

I know Betta are violent by nature, but is there a reason he does this, or a way I can mellow him out a bit?

Hmmm, he must be really territorial. I had a Paradise fish that would attack me when I put my hand in her tank. She got a little better when I moved her to a larger tank. You could try that.
I do not know about Bettas, but Cichlids tend to become less aggressive the more space they have.

Sometimes, when bettas get too aggressive, a change of scenery can lower their agression. Try moving around (drastically) his plants and other decor. It might help. Also, try distracting him while feeding, maybe that will help.

Hmm he's getting even worse now, but he also tore his tail really bad last night so that would explain it. He comes to the top of the tank and thrashes at me, and when I put my hand in for any reason it is a violent all out brawl against it. I dip my finger in, and he'll bite it 6-8 times before i can pull it out. Very aggressive, lol.

But he sure likes the new pink plants, and I have determined he attacks more viciously when I go anywhere near them. He sleeps on them and hides in the cave often, so I am pretty sure that is his problem.